The present invention relates to a method of manufacturing a composite member of metal plates and synthetic resin, and particularly relates to a method of manufacturing a composite member of metal plates and synthetic resin in which the composite member of metal plates and synthetic resin can be easily manufactured, and bending and/or drawing work can be simultaneously performed if necessary.
Conventionally, known are various kinds of method of producing a composite member made of metal plates and synthetic resin layers. For example, in order to produce a composite member having a sandwich structure with a pair of metal plates, there is a typical method in which metal plates are bonded through an adhesive onto opposite surfaces of a synthetic resin plate which is formed platelike through extrusion molding.
However, in the case of producing a composite member having the sandwich structure by such a known method, there has been a problem that the composite member which can be produced is limited to a plate-like one, and any composite member having a solid structure including a bent portion, a drawn portion, or the like, can not be produced. In the case of producing a composite member having a predetermined shape, on the other hand, there has been a problem that at least three steps of preparing metal plates by punching, preparing a synthetic resin plate by molding, and bonding the metal plates onto the synthetic resin plate through an adhesive are required, thereby making the work complicated.
In order to solve the above problems, a method of producing a composite member having a three-layer structure has been proposed, which method comprises the steps of feeding at least two previously rust-prevention-treated metal plates into a metal mold assembly, performing punching and cutting work on the metal plates by using a punch and a die constituting a cavity and a core in the metal mold assembly, slightly opening the metal mold assembly with attracting the two metal plates toward a movable side and a fixed side metal mold, respectively, by means of vacuum or magnetic attraction to thereby form a gap between the metal plates, and pouring adhesive resin into the gap by means of injection molding (U.S. patent application Ser. No. 07/098,795).
In this method, however, there has been a problem that it is necessary to raise the temperature of the metal mold assembly up to 70.degree.-90.degree. C. in order to cause the adhesive resin to tightly adhere to the metal plates, so that the metal mold assembly expands to thereby make it impossible to secure a clearance necessary to perform press working and the press working becomes difficult.